parse multiple COMMUNITIES value.

svn path=/trunk/; revision=1556

1 files changed, 113 insertions, 70 deletions

diff --git a/packet-bgp.c b/packet-bgp.c
index aafe62bfb3..205bd84485 100644
--- a/packet-bgp.c
+++ b/packet-bgp.c
@@ -197,6 +197,7 @@ static gint ett_bgp_open = -1;
 static gint ett_bgp_update = -1;
 static gint ett_bgp_notification = -1;
 static gint ett_bgp_as_paths = -1;
+static gint ett_bgp_communities = -1;
 
 /*
  * Decode an IPv4 prefix.
@@ -298,24 +299,27 @@ static void
 dissect_bgp_update(const u_char *pd, int offset, frame_data *fd,
     proto_tree *tree)
 {
-    struct bgp bgp;                        /* BGP header            */
-    struct bgp_attr bgpa;                  /* path attributes       */
-    int             hlen;                  /* message length        */
-    const u_char    *p;                    /* packet offset pointer */
-    const u_char    *q;                    /* tmp                   */
-    const u_char    *end;                  /* message end           */
-    int             len;                   /* tmp                   */
-    proto_item      *ti;                   /* tree item             */
-    proto_tree      *subtree;              /* subtree for attibutes */ 
-    proto_tree      *subtree2;             /* subtree for attibutes */ 
-    proto_tree      *subtree3;             /* subtree for attibutes */
-    proto_tree      *as_paths_tree;        /* subtree for AS_PATHs  */
-    proto_tree      *as_path_tree;         /* subtree for AS_PATH   */
-    int             i, j;                  /* tmp                   */
-    guint8          length;                /* AS_PATH length        */
-    guint8          type;                  /* AS_PATH type          */
-    char            *as_path_str = NULL;   /* AS_PATH string        */
-    char            junk_buf[256];         /* tmp                   */
+    struct bgp bgp;                            /* BGP header              */
+    struct bgp_attr bgpa;                      /* path attributes         */
+    int             hlen;                      /* message length          */
+    const u_char    *p;                        /* packet offset pointer   */
+    const u_char    *q;                        /* tmp                     */
+    const u_char    *end;                      /* message end             */
+    int             len;                       /* tmp                     */
+    proto_item      *ti;                       /* tree item               */
+    proto_tree      *subtree;                  /* subtree for attibutes   */ 
+    proto_tree      *subtree2;                 /* subtree for attibutes   */ 
+    proto_tree      *subtree3;                 /* subtree for attibutes   */
+    proto_tree      *as_paths_tree;            /* subtree for AS_PATHs    */
+    proto_tree      *as_path_tree;             /* subtree for AS_PATH     */
+    proto_tree      *communities_tree;         /* subtree for COMMUNITIES */
+    proto_tree      *community_tree;           /* subtree for a community */
+    int             i, j;                      /* tmp                     */
+    guint8          length;                    /* AS_PATH length          */
+    guint8          type;                      /* AS_PATH type            */
+    char            *as_path_str = NULL;       /* AS_PATH string          */
+    char            *communities_str = NULL;   /* COMMUNITIES string      */
+    char            junk_buf[256];             /* tmp                     */
 
 
     /* snarf UPDATE message */
@@ -486,29 +490,48 @@ dissect_bgp_update(const u_char *pd, int offset, frame_data *fd,
                         (alen + aoff == 1) ? "byte" : "bytes");
 		break;
             case BGPTYPE_COMMUNITIES:
-		if (alen != 4)
+		if (alen % 4 != 0)
 		    goto default_attribute_top;
 
-                /* check for well-known communities */
-		if (pntohl(&p[i + aoff]) == BGP_COMM_NO_EXPORT)
-                    strncpy(junk_buf, "NO_EXPORT", 10);
-		else if (pntohl(&p[i + aoff]) == 
-                        BGP_COMM_NO_ADVERTISE)
-                    strncpy(junk_buf, "NO_ADVERTISE", 13);
-		else if (pntohl(&p[i + aoff]) == 
-                        BGP_COMM_NO_EXPORT_SUBCONFED)
-                    strncpy(junk_buf, "NO_EXPORT_SUBCONFED", 20);
-                else {
-                    snprintf(junk_buf, sizeof(junk_buf), "%u:%u",
-		            pntohs(&p[i + aoff]), 
-                            pntohs(&p[i + aoff + 2]));
-                }
+		/* (p + i + 3) =
+		   (p + current attribute + 3 bytes to first tuple) */ 
+		end = p + alen + i + 3;
+		q = p + i + 3;
+		/* must be freed by second switch!                          */
+		/* "alen * 12" (5 digits, a :, 5 digits + space ) should be 
+		   a good estimate of how long the communities string could 
+		   be                                                       */
+		communities_str = malloc((alen + 1) * 12);
+		if (communities_str == NULL) break;
+		communities_str[0] = '\0';
+		memset(junk_buf, 0, sizeof(junk_buf)); 
+
+		/* snarf each community */
+		while (q < end) {
+		    /* check for well-known communities */
+		    if (pntohl(q) == BGP_COMM_NO_EXPORT)
+			strncpy(junk_buf, "NO_EXPORT ", 10);
+		    else if (pntohl(q) == BGP_COMM_NO_ADVERTISE)
+			strncpy(junk_buf, "NO_ADVERTISE ", 13);
+		    else if (pntohl(q) == BGP_COMM_NO_EXPORT_SUBCONFED)
+			strncpy(junk_buf, "NO_EXPORT_SUBCONFED ", 20);
+		    else {
+			snprintf(junk_buf, sizeof(junk_buf), "%u:%u ",
+				pntohs(q), 
+				pntohs(q + 2));
+		    }
+		    q += 4; 
+
+		    strncat(communities_str, junk_buf, sizeof(junk_buf));
+		}
+		/* cleanup end of string */
+		communities_str[strlen(communities_str) - 1] = '\0';
 
 		ti = proto_tree_add_text(subtree, p - pd + i, alen + aoff,
 			"%s: %s (%u %s)",
 			val_to_str(bgpa.bgpa_type, bgpattr_type, "Unknown"),
-                        junk_buf, alen + aoff,
-                        (alen + aoff == 1) ? "byte" : "bytes");
+			communities_str, alen + aoff,
+			(alen + aoff == 1) ? "byte" : "bytes");
 		break;
 	    case BGPTYPE_ORIGINATOR_ID:
 		if (alen != 4)
@@ -517,7 +540,7 @@ dissect_bgp_update(const u_char *pd, int offset, frame_data *fd,
 			"%s: %s (%u %s)",
 			val_to_str(bgpa.bgpa_type, bgpattr_type, "Unknown"),
 			ip_to_str(&p[i + aoff]), alen + aoff, (alen + aoff == 1)
-                        ? "byte" : "bytes");
+				? "byte" : "bytes");
 		break;
 	    case BGPTYPE_CLUSTER_LIST:
 	    default:
@@ -723,43 +746,62 @@ dissect_bgp_update(const u_char *pd, int offset, frame_data *fd,
 		}
 		break;
             case BGPTYPE_COMMUNITIES:
-		if (alen != 4) {
-		    proto_tree_add_text(subtree2, p - pd + i + aoff, 4, 
+		if (alen % 4 != 0) {
+		    proto_tree_add_text(subtree2, p - pd + i + aoff, alen, 
 			    "Communities (invalid): %u %s", alen,
                             (alen == 1) ? "byte" : "bytes");
                 }
-                /* check for reserved values */
-		else if (pntohs(&p[i + aoff]) == FOURHEX0 ||
-		        pntohs(&p[i + aoff]) == FOURHEXF) {
-                    /* check for well-known communities */
-		    if (pntohl(&p[i + aoff]) == BGP_COMM_NO_EXPORT)
-		        proto_tree_add_text(subtree2, p - pd + i + aoff, 4, 
-                                "Communities: NO_EXPORT (0x%x)", 
-                                pntohl(&p[i + aoff]));
-		    else if (pntohl(&p[i + aoff]) == 
-                            BGP_COMM_NO_ADVERTISE)
-		        proto_tree_add_text(subtree2, p - pd + i + aoff, 4, 
-                                "Communities: NO_ADVERTISE (0x%x)",
-                                pntohl(&p[i + aoff]));
-		    else if (pntohl(&p[i + aoff]) == 
-                            BGP_COMM_NO_EXPORT_SUBCONFED)
-		        proto_tree_add_text(subtree2, p - pd + i + aoff, 4, 
-                                "Communities: NO_EXPORT_SUBCONFED (0x%x)",
-                                pntohl(&p[i + aoff]));
-                    else {
-		        proto_tree_add_text(subtree2, p - pd + i + aoff, 4, 
-                                "Communities (reserved): 0x%x",
-		                pntohl(&p[i + aoff]));
-                    }
-                }
-                else {
-		    proto_tree_add_text(subtree2, p - pd + i + aoff, 2, 
-                            "Communities AS: %u", 
-                            pntohs(&p[i + aoff]));
-		    proto_tree_add_text(subtree2, p - pd + i + aoff + 2, 2, 
-                            "Communities value: %u", 
-                            pntohs(&p[i + aoff + 2]));
-                }
+
+		ti = proto_tree_add_text(subtree2, p - pd + i + aoff, alen,
+			"Communities: %s", communities_str);
+		communities_tree = proto_item_add_subtree(ti, 
+			ett_bgp_communities);
+
+		/* (p + i + 3) =
+		   (p + current attribute + 3 bytes to first tuple) */
+		end = p + alen + i + 3;
+		q = p + i + 3;
+
+		/* snarf each community */
+		while (q < end) {
+		    /* check for reserved values */
+		    if (pntohs(q) == FOURHEX0 || pntohs(q) == FOURHEXF) {
+			/* check for well-known communities */
+			if (pntohl(q) == BGP_COMM_NO_EXPORT)
+			    proto_tree_add_text(communities_tree, 
+				   q - pd - 3 + aoff, 4, 
+				   "Community: NO_EXPORT (0x%x)", pntohl(q));
+			else if (pntohl(q) == BGP_COMM_NO_ADVERTISE)
+			    proto_tree_add_text(communities_tree, 
+				   q - pd - 3 + aoff, 4, 
+				   "Community: NO_ADVERTISE (0x%x)", pntohl(q));
+			else if (pntohl(q) == BGP_COMM_NO_EXPORT_SUBCONFED)
+			    proto_tree_add_text(communities_tree, 
+				    q - pd - 3 + aoff, 4, 
+				    "Community: NO_EXPORT_SUBCONFED (0x%x)",
+				    pntohl(q));
+			else
+			    proto_tree_add_text(communities_tree, 
+				    q - pd - 3 + aoff, 4, 
+				    "Community (reserved): 0x%x", pntohl(q));
+		    }
+		    else {
+
+			ti = proto_tree_add_text(communities_tree,
+				q - pd - 3 + aoff, 4, "Community: %u:%u", 
+				pntohs(q), pntohs(q + 2));
+			community_tree = proto_item_add_subtree(ti, 
+			    ett_bgp_communities);
+			proto_tree_add_text(community_tree, q - pd - 3 + aoff,
+				2, "Community AS: %u", pntohs(q));
+			proto_tree_add_text(community_tree, q - pd - 1 + aoff, 
+				2, "Community value: %u", pntohs(q + 2));
+		    }
+
+		    q += 4;
+		}
+
+		free(communities_str);
 		break;
 	    case BGPTYPE_ORIGINATOR_ID:
 		if (alen != 4) {
@@ -1154,6 +1196,7 @@ proto_register_bgp(void)
       &ett_bgp_update,
       &ett_bgp_notification,
       &ett_bgp_as_paths,
+      &ett_bgp_communities,
     };
 
     proto_bgp = proto_register_protocol("Border Gateway Protocol", "bgp");